This doesn't really seem that headline-worthy. It's not like it's a new Perry position. He's always been against subsidies for anything except Texas's cash crop, oil. He made an issue of ethanol in 2008, and he stood by his position (in at least a half-assed way) during the period around his presidential announcement and the Ames Straw Poll.
But, says the Fox story, "Perry brought up ethanol during a jobs forum in Pella in response to a question about whether wind energy subsidies should continue." (emphasis mine).
So what this really amounts to is that he's trying to dial back expectations in Iowa, where he's already trailing badly in the polls and probably doesn't have time to catch up (even if time was the only thing he needed to catch up). He'll start shifting campaign resources out of the state (if he hasn't already), then try to write a poor showing in the Iowa caucus off to "they didn't like what I said about ethanol" and see if he can make his stand with a credible second in New Hampshire and some wins after that.